Explain the concept of data consistency in distributed databases. How does it differ from data consistency in centralized databases? Discuss techniques used to maintain data consistency in a DDBMS.

Data consistency in databases ensures that data remains accurate and reliable during any operation (like insert, update, or delete).

Data Consistency in Centralized vs. Distributed Databases:
Centralized Databases:

Definition: A centralized database exists on a single computer or server and is accessed by users over a network.
Consistency: In a centralized system, ensuring data consistency is relatively straightforward since all operations are performed on a single data store. Atomicity, Consistency, Isolation, Durability (ACID) properties are often employed to ensure reliable processing of transactions.